The present invention relates to magnetic disk units, and in particular to a magnetic head slider and its suspension structure in a magnetic disk unit of the contact recording type in which a magnetic head slider is brought into contact with a magnetic disk.
In order to increase the recoding density of magnetic disk units, the flying height between a slider for mounting a magnetic head and a magnetic disk has tended to be reduced. As the flying height is reduced, contact between the slider and the magnetic disk is becoming inevitable. Thus, there has been proposed a magnetic disk unit of the so-called contact recording type in which magnetic recording is performed with the slider brought into contact with the magnetic disk from the beginning.
In U.S. Pat. No. 5,041,932, there is disclosed an integral magnetic head/suspension structure formed as a long and slender bent dielectric object or as a suspension having a magnetic head on one end thereof. This integral magnetic head/suspension has a feature of extremely light mass. By reducing the mass of the integral magnetic head/suspension, the load applied to the magnetic disk can be reduced and wear between the magnetic head/slider and the magnetic disk can be reduced.
In a structure proposed in JP-A-6-251528, the flying force generated by the air flow caused by rotating the magnetic disk under the integral magnetic head/suspension assembly is canceled by mounting the suspension section so as to form a suitable angle with respect to the surface of the magnetic disk and thereby causing a compressive force due to air flow to act. In this structure, the contact state is maintained over the entire surface of the magnetic disk.
In a positive pressure slider of flying/contact mixture type proposed in JP-A-5-74090 and JP-A6-052645, a magnetic head is disposed on a center rail formed on a trailing edge of a positive pressure slider of a flying type, and only the center rail having the magnetic head is brought into contact with a magnetic disk to conduct magnetic recording.
In a negative pressure slider of the flying/contact mixture type proposed in JP-A-62-167610, a trailing edge of a negative pressure slider of a flying type is brought into contact with a magnetic disk to conduct magnetic recording.
An object of the present invention is to reduce, in magnetic disk units of the contact recording type, contact force between a slider and a magnetic disk so as not to damage the slider and the magnetic disk fatally.
Another object of the present invention is to provide a magnetic disk unit capable of maintaining uniform contact force over the entire surface of a magnetic disk and conducting stable contact recording over a long period.
Another object of the present invention is to decrease frictional force caused in a contact portion between a slider and a magnetic disk when the slider is positioned on a data track on the magnetic disk by an actuator arm to such a degree as not to affect the positioning accuracy.
Still another object of the present invention is to restrict jumping of a slider from a magnetic disk caused by unsteady contact force, debris on the magnetic disk, or vibration of the magnetic disk unit.
In accordance with a first aspect of an embodiment of the present invention, a first pad including a magnetic head and second pads which do not include a magnetic head are provided on an air bearing surface of a slider of a magnetic disk unit. A part of the first pad keeps in contact with a magnetic disk when the magnetic disk is rotated, and a load point is positioned between a leading edge of the slider and a position located at a distance of approximately 0.42 times the whole length of the slider from the leading edge of the slider.
In accordance with a second aspect of an embodiment of the present invention, a trailing pad including a magnetic head and other pads which do not include a magnetic head are provided on an air bearing surface of a slider of a magnetic disk unit, and only the trailing pad keeps in contact with the magnetic disk while the magnetic disk is being rotated whereas other pads are kept apart from and fly over the magnetic disk due to an air flow caused by the rotation of the magnetic disk, the contact force between the trailing end pad and the magnetic disk being at most 200 mgf.
In accordance with a third aspect of an embodiment of the present invention, a slider having a magnetic head includes, in its air bearing surface, a first pair of positive pressure side pads located on the leading side, a second pair of positive pressure side pads located nearly in the center in the slider length direction, and a positive pressure center pad. Located on the trailing edge side and containing the magnetic head, the area of the second positive pressure side pads being greater than the area of the first positive pressure side pads and the area of the positive pressure center pad.
In accordance with a fourth aspect of an embodiment of the present invention, a first pad including the magnetic head and second pads including no magnetic heads are disposed on the air bearing surface of the slider, and flying force generated by the first pad is sufficiently smaller than flying force generated by the second pads. The magnitude and pressure center of the flying force generated by the second pads is substantially coincident with the magnitude of the load driven to the slider by the suspension and the load point, and the slider is provided by a gimbal of the suspension with a moment force in such a direction as to make the first pad approach the magnetic disk, only the first pad keeping in contact with the magnetic disk during rotation of the magnetic disk.